[jdk17u-dev] RFR: 8290209: jcup.md missing additional text

[Goetz Lindenmaier]

I backport this for parity with 17.0.5-oracle.

-------------

Commit messages:
 - Backport 2bf6285c80f078d8451afb5682ee307bb13be179

Changes: https://git.openjdk.org/jdk17u-dev/pull/673/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=673&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290209
  Stats: 11 lines in 1 file changed: 9 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/673.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/673/head:pull/673

PR: https://git.openjdk.org/jdk17u-dev/pull/673